Means for dip-forming

ABSTRACT

Wires, rods, or, tubes upon which melt is to be applied are passed through a dip-forming crucible. U-shaped heaters are placed at the sides of the crucible and can be moved away from the crucible.

[ Aug. 27, 1974 United States Patent [191 Karlsson et al.

[ MEANS FOR DIP-FORMING [56] References Cited UNITED STATES PATENTS 2,052,010 8/1936 Bailey.......................... 3,165,572

[75] Inventors: Gosta Kaflsson, Vasteras; Borje Nilsson, Halsingbqrg, both of Sweden 219/1019 X 1/1965 Burtenshaw et 13/27 Primary Examiner-Roy N. Envall Jr.

[22] Filed:

Attorney, Agent, or FirmKeny0n & Kenyon Reilly Carr & Chapin 21 App]. No.2 256,588

mww ww Ph m as m m b oei mqmm a m W 0 6 .l m ...F T n g .w .m. A mw m odw a fl.

m n cm .m e mw mm .w mmm mc m u dr. tue a o y rraa D .w

t S a m a TS W "M o le wm 7.nepaw .UWmhb 1 769 H HA 4 350 5 1 1 b i 7 59 m WW4 m mum u m ""9 u WW I" .mm I. n n H .mm m md mm .lm m n mm D. n A In l m m In C c... r l 0 C Fm n l nw m. UIF 1 1]] 0 2 00 3 555 [[l PATENTEDAUGZTISH uv H MEANS FOR DIP-FORMING BACKGROUND OF THE INVENTION The present invention relates to a means for dipforming elongate metal objects having a casting crucible for transporting the object while molten metal is being applied.

Such devices have been known for a long time and are shown in Swedish Pat. Nos. 195,558 and 307,629, for example. Here it is shown how molten material, having approximately the same composition as the elongate body, flows down from a smelting furnace along a heated pipe down into a crucible, where the material forms a melt through which a wire, rod or tube or the like passes approximately vertically (horizontal passage is also known). The molten material in the crucible is deposited on the elongate body and increases its cross-sectional area to a considerable extent. After calibration, the thicker body passes through a cooled pipe to a rolling mill or a wire, rod or tube drawing apparatus.

Heating and preheating members such as induction heaters are arranged around the crucible or in the walls of the crucible to prevent the melt in the crucible from freezing, or at any rate from becoming'too cold.

ln designs now existing, the induction coil is sometimes even wound around the insulating compound (gaifilin) in the crucible which causes accidents because copper (melt) comes into contact with the coil and causes water leakage.

Another drawback with conventional arrangements is that the coil is in the way when the crucible is being inspected or taken apart. Another drawback is that it makes the equipment considerably more expensive.

SUMMARY OF THE INVENTION The invention according to this application aims at a solution of these and other similar problems and is characterised in that a substantially fiat induction heater is arranged around the crucible along at least one of its sides and movable in relation to the crucible. With the help of such a heater it is possible to preheat the melt in the crucible as well as keeping it warm and even reheating it. At the same time the heater can easily be moved to the side for various reasons, such as when inspecting and repairing the crucible, when replacing a heater, to use the same heater for several crucibles, etc.

In a preferred embodiment. the heater is designed so that it surrounds the crucible on three sides, there being induction heaters, for example wound in flat spirals or zig-zag, or in the shape of concentric semicircles, mutually series-connected, in each of the three sides facing the crucible.

THE DRAWING The invention is further exemplified in the accompanying drawings in which FIG. 1 shows one side of a heater and FIG. 2 the same heater seen from above. FIG. 3 shows finally a fixed part of the heating winding.

PREFERRED EMBODIMENT FIG. I shows one side of the U-shaped heater to be placed around the dip-forming crucible II. The wire (or rod or tube) upon which the melt is to be applied is shown at 12, and after melt has been deposited a wire is taken out at 13 having a larger area. The crucible II can be constructed in the manner shown and described,

in US. Pat. No. 3,466,l86. Melt is introduced into the crucible l l at 14. At the side the liquid-filled-conductors 15 to the induction heater are applied fiat, here in the form of a number of series-connected semi-circles,.

hollow, carrying liquid. Each of the sides of the U- shaped heater may be designed in the same way and the conductors of the sides may even be mutually series connected. The walls of the heater may be mutually attached or they may be arranged to swing about a hinge (not shown).

The wires may also be applied as flat spirals, zig-zag or in concentric circles, etc. on each side and should be fed with current having a frequency of 50l0,000 Hz, here, for example, 4,000 Hz.

The U-shaped heater (see FIG. 2) can be moved with respect to the crucible 1l,for example it can be placed on a trolley, be provided with wheels or be made liftable so that it can be moved away from the crucible, for example for repair or inspection, or to be used for several different crucibles.

The U-shaped heater consists, inter alia, of an insu- Iating layer 16 of, for example, glass laminate or asbestos. The conductors 15 are attached on the inside of layer 16 in the most suitable manner, for example by means of bolts 17, (see FIG. 3). Screw 18 having outer. insulated heads 19, for example of nylon, are screwed through holes in the layer 16 into a nut 20 attached to the conductor 15. The conductors may of course he attached in a number of different ways.

The heater may also be swung away from the crucible in order to enable repairs and/or inspection to be carried out. The risk of leakage in the insulating body 16 from the crucible 11 is slight, as is the risk of melt coming into direct contact with the winding. Preheating and heat-retaining in the melt can be performed at any time without disturbances in operation.

In FIG. 1 the heater is schematically shown as mounted on a trolley comprising a flat body 22 on which the insulating layer 16 of the crucible is mounted. The trolley has wheels 23 so it may be run free from the crucible ll, the latter being suitably suspended free from the trolley. Thus, the heater is movable in relation to the crucible.

The arrangement described above can be varied in many ways within the scope-of the following claims.

What is claimed is:

1. An apparatus for dip-forming elongated metal objects, said apparatus having a casting crucible through which a metal object is transported and wherein molten metal is applied to the object, and improved heating means for said crucible comprising an induction heater having three substantially flat members forming a U- shaped structure and means for mounting said structure removably adjacent three corresponding sides of the crucible.

2. The invention according to claim 1 wherein a plurality of water-cooled conductors are mounted to the inside of said three flat members.

3. The invention according to claim 2 wherein said conductors on the inside of said flat members are wound to form flat spirals. 

1. An apparatus for dip-forming elongated metal objects, said apparatus having a casting crucible through which a metal object is transported and wherein molten metal is applied to the object, and improved heating means for said crucible comprising an induction heater having three substantially flat members forming a U-shaped structure and means for mounting said structure removably adjacent three corresponding sides of the crucible.
 2. The invention according to claim 1 wherein a plurality of water-cooled conductors are mounted to the inside of said three flat members.
 3. The invention according to claim 2 wherein said conductors on the inside of said flat members are wound to form flat spirals. 